897 research outputs found
Tolerance Mechanisms in Mercury-exposed Chromolaena Odorata (L.f.) R.M. King Et H. Robinson, a Potential Phytoremediator
Chromolaena odorata (L.f.) R.M. King et H. Robinson plants were grown in Hoagland\u27s solutions with 0.00 ppm and 1.00 ppm Hg(NO3)2. The calcium, magnesium, iron, and sulfur levels in the leaves were found to be not significantly affected by presence of the uptaken Hg2+. The chlorophyll a, chlorophyll b, and total chlorophyll contents of its leaves also remained within normal levels, which may indicate that the photosynthetic machinery of the Hg-exposed C. odorata was unaffected by the presence of Hg2+. The results of the ICP-AES analyses of the Hg2+ contents established the presence of Hg2+ in all the subcellular components obtained from the leaves of the Hg-treated C. odorata plants, and that the ultimate localization of Hg2+ is in the vacuoles. The findings revealed no significant differences in the degree of oxidative injury between the cells from the control and Hg-treated plants, as evidenced by the low lipid peroxidation levels obtained with the TBARS assay. The SH-containing biomolecules that were initially detected through DTNB assay manifested a predominant peak in the RP-HPLC chromatographs of both the control and Hg-treated plants, with their retention times falling within the ranges of GSH, MT, and cysteine standards. However, the concentrations of the GSH- and/or MT-like, Cys-containing biomolecules detected in the leaves of Hg-treated C. odorata plants were ten times higher than those of the control.The findings of this study suggest that the enhanced antioxidative capacity, the production of Hg-binding biomolecules, and the localization of Hg2+ ions ultimately in the vacuoles of the leaves are the mechanisms which bring about Hg2+ tolerance and homeostasis in C. odorata plant. These results indicate that C. odorata is a potentially effective phytoremediator for Hg2+
Conferência de busca de futuro: relatório final.
Introdução; Metodologia; Focalizando o passado; Focalizando o presente; Focalizando o futuro; Pós-Conferência.bitstream/item/37176/1/Doc51.pd
Immobilization And Photoacoustic Spectroscopy Of N-(2-pyridyl)acetamide Cation Complexes Bonded To Silica Gel
N-(2-Pyridyl)acetamide was covalently immobilized onto silica gel giving 1.57×10-4 mol of this molecule per gram of silica. This new bidentate chelate extracts MCl2 (M = Ni, Co, Cu) from ethanol and acetone solutions. The photoacoustic spectra of the solid complexed samples were obtained in the visible and near-infrared spectral regions and were analysed using ligand field theory. The calculated Racah parameters indicate a tetrahedral geometry for nickel and cobalt and a highly distorted octahedral geometry for the copper complex.3547948213SDG16840035; AHA; American Heart Associatio
Master Operators Govern Multifractality in Percolation
Using renormalization group methods we study multifractality in percolation
at the instance of noisy random resistor networks. We introduce the concept of
master operators. The multifractal moments of the current distribution (which
are proportional to the noise cumulants of the
resistance between two sites x and located on the same cluster) are
related to such master operators. The scaling behavior of the multifractal
moments is governed exclusively by the master operators, even though a myriad
of servant operators is involved in the renormalization procedure. We calculate
the family of multifractal exponents for the scaling behavior of the
noise cumulants, ,
where is the correlation length exponent for percolation, to two-loop
order.Comment: 6 page
Effects of surfaces on resistor percolation
We study the effects of surfaces on resistor percolation at the instance of a
semi-infinite geometry. Particularly we are interested in the average
resistance between two connected ports located on the surface. Based on general
grounds as symmetries and relevance we introduce a field theoretic Hamiltonian
for semi-infinite random resistor networks. We show that the surface
contributes to the average resistance only in terms of corrections to scaling.
These corrections are governed by surface resistance exponents. We carry out
renormalization group improved perturbation calculations for the special and
the ordinary transition. We calculate the surface resistance exponents
\phi_{\mathcal S \mathnormal} and \phi_{\mathcal S \mathnormal}^\infty for
the special and the ordinary transition, respectively, to one-loop order.Comment: 19 pages, 3 figure
Percolation Threshold, Fisher Exponent, and Shortest Path Exponent for 4 and 5 Dimensions
We develop a method of constructing percolation clusters that allows us to
build very large clusters using very little computer memory by limiting the
maximum number of sites for which we maintain state information to a number of
the order of the number of sites in the largest chemical shell of the cluster
being created. The memory required to grow a cluster of mass s is of the order
of bytes where ranges from 0.4 for 2-dimensional lattices
to 0.5 for 6- (or higher)-dimensional lattices. We use this method to estimate
, the exponent relating the minimum path to the
Euclidean distance r, for 4D and 5D hypercubic lattices. Analyzing both site
and bond percolation, we find (4D) and
(5D). In order to determine
to high precision, and without bias, it was necessary to
first find precise values for the percolation threshold, :
(4D) and (5D) for site and
(4D) and (5D) for bond
percolation. We also calculate the Fisher exponent, , determined in the
course of calculating the values of : (4D) and
(5D)
Expected investment of Tocantins farmers, Brazil, to apply integrated crop-livestock system during Embrapa's technology transfer
In this presentation, we report the data of these farmers collected in the beginning of the project to analyze their current conditions and expectations regarding the implementation of the new integrated system
Logarithmic Corrections in Dynamic Isotropic Percolation
Based on the field theoretic formulation of the general epidemic process we
study logarithmic corrections to scaling in dynamic isotropic percolation at
the upper critical dimension d=6. Employing renormalization group methods we
determine these corrections for some of the most interesting time dependent
observables in dynamic percolation at the critical point up to and including
the next to leading correction. For clusters emanating from a local seed at the
origin we calculate the number of active sites, the survival probability as
well as the radius of gyration.Comment: 9 pages, 3 figures, version to appear in Phys. Rev.
Agricultura apoiada pela comunidade: poderia a experiência dos agricultores americanos ser útil para os agricultores urbanos brasileiros?
O objetivo deste trabalho foi obter algumas informações sobre o projeto Agricultura Apoiada pela Comunidade (AAC) nos EUA e avaliar se consumidores e produtores urbanos pobres de uma cidade brasileira de baixa renda aceitariam se engaja neste tipo de projeto
Relative water content in two grass cultivars in crop-livestock system in the State of Tocantins, Brazil.
In this presentation, we report the results of two grasses on Integrated Crop-Livestock System in the Tocantins Cerrado
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